Process of precipitating zeinfkom



April 15, 1941. A. lc. HoREsl ET AL 2,238,591

PROCESS. OF PRECPITATING ZEIN FROM ITS SOLUTION V Filed Jpne 18, 1938Patented Apr. 15, 1941 UNITED sk'niries PAT-ENT OFFICE assignors, bymesne assignments, to Corn Prodnets Refining Company, New York, N: Y., acorporation of New Jersey Application June 1s, 193s, semina. 214,512 i 7claims. `(el. 1li- 54) This invention relates to the precipitation ofzein from its solution. The primary object of the invention is toprovide a new and improved method whereby the zein may be precipitatedin the form of small solid particles' of filamentary 5 or fibrouscharacter which can be dried, and if need be, further comminuted, togive a dry, gran/u1- lar, free-iiowing material. f.

It has been customary to precipitate zein'from the form of a dough whichis then rolled out into sheets and the sheets soaked in water in orderto. complete the precipitation of the -zein by removal of residualsolvent. The process of the instant invention is more expeditious,convenient and economical than the process just outlined and givesaproduct of better qualit J In accordance with this invention, the zeinsolution is projected inthe form of a fine stream (which might bemultiplied) into a flowing body of precipitating agent, preferablywater, which, however, may contain some of the solvent alcohol; and thestream of zein solution is changed into solid threads, filaments or bresof zein by the dmusion of the solvent from the zein into the flowingbody ofwater; the zein mass in its fibrous or f'llamentary form beingcarried along by the water, until precipitation is complete, and sub"stantially all of the solvent removed, the material being preferablyaerated so that in the final stageof the flow it will float; whereuponthe zein mass is withdrawn from the water and dried. It -would vbepossible'toform the projected streams of the zein solution by forcingthe solution through one or more very minute orifices; but a morepractical 3" way is that disclosed herein in accordance with Y which thesolutionrr passes under pressure through a fairly large orifice, sayone-sixteenth-of an inch zein stream by the velocity and turbulence oithe surrounding water envelope is drawn out to a small diameter andbroken `up into a loose mass of short fibrous, thread-like oriilamentary bodies'. The air for aerating and floating the zein mass inthe water may be and is preferably introduced through the water nozzlewhich forms the water 50 envelope just referred to. j

' Apparatus suitable for practicingthe process of this invention isshown in the accompanying drawing which is a diagrammatic layout of ation, howeveryis not limited to this or to any other particular form ofapparatus.

Referring to the drawing, A is a nozzle consisting of an inner tubularmember I for the zein solution and an outer concentric tubular member 2through which is forced an aqueous dispersing and precipitating mediumreferred to above as the water envelope; the nozzle members .i beingpreferably formed with sharply tapered its solution, in aqueous alcohol,for example, in 10 ends la and 2a, respectively, providing restrictedoutlet orifices 3 and I, The forward end of the nozzle Ais enclosedin aconduit 5, of which pipe 6v is a continuation which extends to the weirchain drag Il carries the zein filaments, which.

beingv aerated, float on the surface of the liquid in the flotation tankB, into a mixing box il,

strings IG of which deliver the dewatered zein to V a conduit il`leading to a spray drier D. The material may be ground before beingspray-dried.

The process involves preferably a continuous circulation of water, fromwhich some is withdrawn continuously,v for the recovery of the zeinsolvent; and the circulatory system is constituted Y Y as follows:

. Fresh water enters at 29 and is used for Washing the zein on filter C.Filtrate and wash water from filter C pass through pipe I8' to receiverE connected by a pipe I9 `with the vacuum pump (not shown) for operatingthe lter. From receiver E the filtrate is forced, by pump 2|; in

part' throughpipe I3 to mixing box Il; in part 40 through pipe 24 to acooler F and thence, through pipe 22-23 -to the outer or envelopeforming member 2 of nozzle A. Water is withdrawn from the flotationvessel B and introduced into'pipe 2| by pump 26 located in pipe 21. ofwater and alcohol mixture is withdrawn from the circulatory systemthrough pipe 28 leading to .the solvent recovery system. ThisAwithdrawal, .conditioned by the amount of fresh water introduced at Il,is so calculated as to maintain -a relatively low alcohol Ycontent inVthe precipitating mediumfor insuring' precipitation of the zein,

but a high Venough concentration to make recovery of the solventdischarged at 2l profitable.

preferred form of yauch apparatus. The inven- Compressed airisintroduced into the induction A vcertain amount pipe 23 of the outermember 2 of nozzle A through branch pipe 30. The purpose of this is toaerate the zein when reduced to the lamentary form, so as to insure theflotation thereof in vessel B through which the velocity of flow isnecessarily retarded. The air could be introduced at any suitable pointin the system.

In practicing the process it is preferable to use a relatively heavyzein solution. one containing between and 30 parts by weight of proteinper 100 parts of zein solution, although operation within this range isnot essential. A suitable solution is one which is obtained by treatingthe zein extract with enough of a hydrocarbon, or other solvent of maizeoil and coloring matter, to bring about a separation of the mixture intotwo liquid phases, the heavier of which contains the zein; this heavyliquid being used either directly in the precipitating operation. orafter dilution with alcohol, or after removal of oil solvent bydistillation. VThe precipitating medium is cooled in cooler F to atemperature between 30 F. and 68 F. It should not be substantially inexcess of 68 F, (20 C.) and preferably is below 59 F.

^ C.) It may have an alcohol content of 10% rounding nozzle member 2 maybe between of an inch and 54; of an inch in diameter. The pressure ofthe zein solution is preferably from 25 to 50 pounds per square inch andits rate of feed from 5 to 20 gallons per hour. The pressure of thedispersing fluid passing through nozzle'miember 2 may be 30-40 poundsper square inch and its rate of ilow 70 to 150 gallons per hour. Theseconditions are not to be regarded as limitations.

Under these or similar conditions the zein issues from the spray nozzlein the form of a stream of liquid about of an inch in diametersurrounded by a concentric envelope of water which moves at highervelocities than the zein stream and the main water stream throughconduit 5-6 and is directed inwardly against the zein stream by theconical form 2a of the nozzle member 2. The zein is drawn out into avery ne stream by the velocity and turbulence of the surrounding waterenvelope and the alcohol solvent of the zein is diffused into the waterof the surrounding envelope and into the larger body of water flowingthrough conduit 5. whereby the zein is precipitated in the form-offilaments about 0.02 to 0.04 of an inch in diameter. As the zeincontinues to move through the conduit 5-6 and through the otation vesselB, further diffusion of solvent takes place, which is very completebecause of the finely divided form of the zein. lWhen dried the laments,which are of spongy character, will crumble into small flakes orparticles so that the material will be granular and relatively freeflowing. The water and air introduced through the nozzle 2 besidesspinning out the zein in fine iilamentary form creates a. turbulence inthe loose mass of laments which tends to disperse the mass in theprecipitating liquid and to bring fresh liquid continuously into contactwith the .zein

Vthreads to promote extraction of the solvent.

ably without departure from the principles of the invention, as will beevident. The intention, in fact, is to. cover all equivalents and allmodifica-V thenozzle at the rate of 7 gallons per hour.

tions of the process within the scope of the appended claims.

Example 1.-The orifice of the zein solution nozzle member is 11; of aninch in diameter and the orice of the surrounding nozzle member 2 7/54of an inch in diameter. The first mentioned orifice being placed 11; ofan inch behind the other. 'Ihe concentration oi the zein is 28 parts byWeight to 100 parts of the solvent. The pres- .sure of the zein solutionon the nozzle is 35 pounds 'per square inch; the water pressure 40pounds per square inch. The zein solution passes through The rate of thewater through the nozzle member 2 is 100 gallons per hour. Theprecipitating medium is circulated through the cooler conduit 5-6 andflotation vessel B at the rate of 40 gallons per minute. The water thuscirculated has an alcohol concentration of about 10% by volume, whereasthe iiltrate from iilter C has a lower concentration, about 5%. Thematerial can be partially de-watered in the filter C to a water contentof about 74% by weight. Drying in the air at room temperature yieldsalight, fluffy zein which dissolves in alcohol with extreme ease.

Example 2.-'Ihe solution is made up of 20 parts of zein, by weight,parts of the solvent, aqueous ethyl alcohol. The nozzle may have thesame dimensions as in Example 1. The pressure of the zein solution inthe nozzle is 50 pounds per square inch and the quantity 20 gallons perhour. The pressure of water in the outer member of the nozzle is 30pounds per square inch and the quantity of water 70 gallons per hour.The water is circulated through conduit 5 past nozzle A at the rate of50 gallons per minute. 'Ihe watervin circulation is maintained at atemperature below 65 F. (18.3 C.). The temperature range may be anywherebetween 30 F. (-l.1 C.) and 68 F. (20 C.), preferably between 50 F. (10C.) and 60 F. (15.6 CL).

AThis application is a continuation in part of co-pending applicationfiled August 18, 1937, Serial No. 159,728.

We claim: 1

1. Process oi. precipitating zein from its solution which comprises:projecting into a moving body of precipitating medium a stream of zeinsolution surrounded by a concentric envelope stream of the precipitatingmedium of suiilcient velocity and turbulence to effect dispersion of thezein in finely divided form.

2. Process of precipitating zein from its solution which comprises:projecting into amoving body of precipitating medium a stream of zeinsolution surrounded by a concentric envelope stream of the precipitatingmedium; and aerating the mixture to keep the zein in suspension.

3. Process of precipitating zein from its solution which comprises:projecting into a moving body of precipitating mediuma stream of zeinsolution surrounded by a. concentric venvelope stream of theprecipitating medium which is inwardly directed against the zein stream.

4. Process of precipitating zein from 'its solution which comprises:injecting into a moving body of precipitating medium a stream of zeinsolution, within an enveloping stream of the precipitating mediumwhereby the zein is reduced to a fllamentary form; and keeping .thesolidified into a moving body of water a stream of zein surrounded by anenveloping stream of water to reduce the zein to a flamentary form.

6. Process of precipitating zein from an alcohol solution of the samewhich comprises: projecting into a moving body of water a stream of zeinsurrounded by an enveloping stream of water and air to reduce the zeinto a lamentary form.

7. Process of precipitating zein from its solution in aqueous alcoholwhich comprises: spraying 10 the solution using water and air as adispersing medium into a rapidly moving body of water; in-

